Employee Benefit Plans - Pension Plan Asset Allocation (Details) - USD ($) $ in Thousands		Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Asset Category
Fair Value of Plan Assets (in dollars)		$ 76,210	[1]	$ 66,159	$ 65,189
Percentage of Plan Assets		100.00%		100.00%
Equity securities
Asset Category
Fair Value of Plan Assets (in dollars)	[1]	$ 46,772
Percentage of Plan Assets		61.00%		60.00%
Fixed income
Asset Category
Fair Value of Plan Assets (in dollars)	[1]	$ 27,887
Percentage of Plan Assets		37.00%		35.00%
Cash equivalents
Asset Category
Fair Value of Plan Assets (in dollars)	[1]	$ 1,551
Percentage of Plan Assets		2.00%		5.00%
Minimum | Equity securities
Asset Category
Target plan asset allocations		50.00%
Minimum | Fixed income
Asset Category
Target plan asset allocations		30.00%
Minimum | Cash equivalents
Asset Category
Target plan asset allocations		2.00%
Maximum | Equity securities
Asset Category
Target plan asset allocations		60.00%
Maximum | Fixed income
Asset Category
Target plan asset allocations		48.00%
Maximum | Cash equivalents
Asset Category
Target plan asset allocations		10.00%

[1] Additional information regarding the fair value of Pension Plan assets as of December 31, 2018 can be found in Note 21, "Fair Value."